Tube drawing apparatus



Nov. 28, 1933. H, HEETKAMP TUBE DRAWING APPARATUS Filed Feb. 9, 1932 UNITED STATES PATENT Q'FFICE TUBE DRAWING APPARATUS Heinrich Heetkamp, Duisburg, Germany, as-

signor to Demag Aktiengesellschaft, Duisburg,

Germany Application February 9, 1932, Serial No. 591,869, and in Germany February 18, 1931 3 Claims.

In tube-drawing benches the work which is pushed over a mandrel is pressed through a number of draw rings disposed one behind the other and thus formed into tubes. The method 5 adopted in the use of this apparatus consists in leaving the mandrel secured to its carrier the mandrel shaft, and withdrawing it from the tubewhich is held fast-during the return movement of the mandrel; or alternatively by releasing the mandrel, and the tube seated thereon from the mandrel shaft after the working stroke, and then securing another cold mandrel to the shaft after its return to the original position. The second of these measures has the advantage over the first mentioned measure that the mandrels last longer as they are given time to cool down gradually in the open air, while in the rst mentioned case the mandrels are cooled with Water in rapid succession. The result is that 20 the mandrels soon become useless, and, moreover, this strain on them is liable to cause variation in the gauge of the tubes.

The invention relates to tube-drawing benches of the type in which the mandrel is detached from its shaft after the working stroke and the drawn tube is stripped from the mandrel outside the bench and is conveyed to a collecting and cooling grid.

In such benches it is customary immediately after the tube drawing operations to pass the tube through a smoothing rolling mill in which not only is the surface of the tube smoothed but the tube is also loosened from the mandrel. The tube is stripped from the mandrel in the next cperation.

In addition to producing ordinary commercial tubes, which have to be finished by being passed through the smoothing rolling mill, it is necessary in practice to produce tubes which by reason ci' the nature of the material and the variations from the normal in diameter and thickness of metal, are not passed through the smoothing rolling mill.

In order to dispense with special apparatus for dealing with such cases as may arise, it is proposed according to the invention to remove the work between the two apparatus referred to, and to provide an auxiliary stripping apparatus which delivers the tubes to the collecting and cooling grid.

Apparatus according to the invention is diagrammatically illustrated by way of example in the accompanying drawing in which Fig. 1 represents a plan of the apparatus, and Figs. 2 to 5 "5 show details on an enlarged scale.

In Figure 1 of the drawing 1 is an oven in which the blanks are heated; these are pierced in the press 2 and are then transferred to the propelling bench 3; after the bench 3 comes thefreducing bed or draw-bench 4, beyond which, and in alignment with the bench 3, is a train of rollers 17. This is succeeded by the smoothing and loosening rolling mill 5, beyond which again is a pair of driving rollers 6 co-operating with the tube guiding channel 7. By the side of and parallel to this channel 7 is a train of rollers 9 provided with a device for gripping the tubes, which device consists substantially of the clamping jaws 8 and driving rollers 10. The chanel 'I and rollers 9 are connected by a guide grid 18. The grid 19, disposed laterally of the rollers 9, serves as a collecting grid for the finished tubes.

The train of rollers 9 extends beyond the pair of rollers 10 and across a guide grid 20 connecting the intermediate train of rollers 17 with a train of delivery rollers 13 disposed parallel to the draw bench 4 and the propelling bench 3. Between the bench 3 and the delivery rollers is a conecting grid 14 on which the mandrels 16 collect and are cooled.

Parallel to the train of rollers 13, and between it and the ring draw bench 4, is a special bed 21 containing a spindle 12 driven by the motor 23 through toothed wheels 22. The free end of the spindle carries tongs 24, serving to grip the mandrels, and in front of the tongs is a ring or plate 11 forming an abutment for the end of the tube.

The apparatus according to the invention operates as follows:

When ordinary commercial tubes are being manufactured the blank 15 (Fig. 2) which has been shaped into the form of a tube on the mandrel in passing through the draw-bench 4 arrives at the rollers 17 and thence passes to the smoothing rolling mill 5. Onr passing from the smoothing rolling mill it is gripped by the rollers 6 and delivered into the channel 7. From this channel the tube with its enclosed mandrel passes over the grid 18 to the rollers 9 in such a position that it is gripped by the jaws 8, Whilst the proled driving rollers 10 (Fig. 3) engage over the end of the mandrel 16 projecting from the tube and draw the latter out of the gripped tube which is then released and run forward on the rollers 9, for delivery on to the lateral collecting grid 19. The mandrel 16 is conveyed in the opposite direction as far as the grid 20, over which it passes to the rollers 13 and is thereby delivered on to the collecting grid 14.

The procedure differs in the case of the special tubes already referred to. In this case the tubes leaving the draw bed 4 are received,` together with mandrels enclosed therein, by the rollers 17 and transferred over the grid 20 tc the rollers 9. The free end of the mandrel is inserted in the tongs 24, the end face of the tube bearing against the plate 11. The motor 23 is then started so that the axially retreating spindle 12 draws the mandrel out of the tube by means of the tongs 24. The nished tube is then conveyed to the collecting grid 19 and the mandrel is transferred laterally from the bench 21 to the train of rollers 13 from which it reaches the cooling grid 14.

The employment of an auxiliary stripping device 12, 24, 11, which is more powerful than the stripping device 8, 10 also has the especial advantage that, in the event of failure of the weaker stripping device, the tube and mandrel can be passed on to the heavier stripper by way of the rollers 9.

I claim:-

1. A tube drawing plant, comprising a drawbench having a plurality of draw rings and a propelling bench, a smoothing rolling mill, a forwarding transfer guide for the drawn tube blank with enclosed mandrel, extending between the draw-bench and the smoothing rolling mill, a mandrel stripper at the rear of the smoothing rolling mill for stripping the mandrel from a tube that has passed through the smoothing rolling mill, a mandrel stripper disposed laterally with respect to the forwarding transfer guide and serving for stripping the mandrel from a tube that is not to pass through the smoothing rolling mill, and a transfer grid connecting the forwarding transfer guide and the second mandrel csV stripper.

2. A tube drawing plant, comprising a drawbench having a plurality of draw rings and a propelling bench, a smoothing rolling mill to the rear of the draw-bench, a forwarding transfer guide for the drawn tube blank with enclosed mandrel connecting the draw-bench and the smoothing rolling mill, a guide to the rear of the smoothing rolling mill to receive the finished tube with enclosed mandrel, a second transfer guide lying parallel with the forwarding transfer guide,

the smoothing rolling mill and the receiving guide, a mandrel stripper for stripping the mandrel from a tube that has passed through the smoothing rolling mill, to co-operate with the second transfer guide and disposed laterally with respect to the receiving guide', a conveyor grid connecting the receiving guide and the second transfer guide, a conveyor guide connecting the forwarding transfer guide and the second transfer guide, and a mandrel stripper for stripping a tube which is not to pass through the smoothing rolling mill from the mandrel, the said mandrel stripper co-operating with the second transfer guide. l

3. A tube drawing plant, comprising a drawbench having a plurality of draw rings and apropelling bench, a smoothing rolling mill to the rear of the draw-bench, a forwarding transfer guide for the drawn tube blank with enclosed mandrel connecting the draw-bench and the smoothing rolling mill, a guide to the rear of the smoothing rolling mill to receive the finished tube with enclosed mandrel, a second transfer guide lying parallel with the forwarding transfer guide, the smoothing rolling mill and the receiving guide, a mandrel stripper for stripping the mandrel from the tube that has passed through the smoothing rolling mill, to co-operate with the second transfer guide and disposed laterally with respect to the receiving guide, a conveyor grid connecting the receiving guide and the second transfer guide, a conveyor guide connecting the forwarding transfer guide and the second transfer guide, a mandrel stripper for stripping a tube which is not to pass through the smoothing rolling mill from the mandrel, the said mandrel stripper co-operating with the second transfer guide, a conveyor grid to the rear of the first mandrel stripper and laterally disposed with reference to the second transfer guide for receiving tubes from the first mandrel stripper, a. third transfer guide parallel with the second transfer guide and serving to receive mandrels from the said mandrel stripper, and a cooling conveyor guide connecting the third transfer guide and the propelling bench for receiving and storing mandrels.

HEINRICH HEETKAMP. 

